Point-of-Care Molecular Test for the Detection of 14 High-Risk Genotypes of Human Papillomavirus in a Single Tube.

Cervical cancers constitute a large disease burden in developing countries, with the human papillomavirus (HPV) being responsible for most cervical lesions. Many regions in low-resource countries lack adequate access to sensitive point-of-care (POC) screening tools, preventing timely diagnosis and treatment. To reduce screening barriers, we developed a POC HPV molecular test that detects 14 high-risk HPV types in 30 min in a single assay. We introduced innovations to the underlying amplification (recombinase polymerase amplification) and detection methodologies such as improved probe design, reagent lyophilization, and pipette-less processing to increase sensitivity while enabling minimally trained personnel to conduct reproducible testing. Based on 198 clinically derived samples, we demonstrated a sensitivity of 93% and a specificity of 73% compared to an FDA-approved polymerase chain reaction-based clinical method. Our modified pipette-less simplified assay had a sensitivity of 96% and a specificity of 83%. The application of our assay is intended as a near-patient screening tool with further evaluation by a clinician for confirmation.

Rapid isothermal point-of-care test for screening of SARS-CoV-2 (COVID-19).

Rapid on-site diagnosis of emerging pathogens is key for early identification of infected individuals and for prevention of further spreading in a population. Currently available molecular diagnostic tests are instrument-based whereas rapid antibody and antigen tests are often not sufficiently sensitive for detection in pre-symptomatic subjects. There is a need for rapid point of care molecular screening tests that can be easily adapted to emerging pathogens and are selective, sensitive, reliable in different settings around the world. We have developed a simple, rapid (<30 â€‹min), and inexpensive test for SARS-CoV-2 that is based on combination of isothermal reverse transcription recombinase polymerase amplification (RT-RPA) using modified primers and visual detection with paper-based microfluidics. Our test (CoRapID) is specific for SARS-CoV-2 (alpha to omicron variants) and does not detect other coronaviruses and pathogens by in silico and in vitro analysis. A two-step test protocol was developed with stable lyophilized reagents that reduces handling by using portable and disposable components (droppers, microapplicators/swabs, paper-strips). After optimization of assay components and conditions, we have achieved a limit of detection (LoD) of 1 copy/reaction by adding a blocking primer to the lateral flow assay. Using a set of 138 clinical samples, a sensitivity of 88.1% (P â€‹< â€‹0.05, CI: 78.2-93.8%) and specificity of 93.9% (P â€‹< â€‹0.05, CI: 85.4-97.6%) was determined. The lack of need for instrumentation for our CoRapID makes it an ideal on-site primary screening tool for local hospitals, doctors' offices, senior homes, workplaces, and in remote settings around the world that often do not have access to clinical laboratories.

Glaucoma in Developing Countries.

Glaucoma is a leading cause of blindness worldwide. The diagnosis and management of glaucoma is especially difficult in the developing countries. Lack of cost effective screening strategies, low income, low rates of literacy and inadequate infrastructures and human resources for eye care services are the obstacles for delivering glaucoma service. Majority of people with glaucoma in developing countries usually present at an advanced stage at the time of diagnosis; which negatively affects their quality of life. Further research, proper allocation of resources and collaborative effort by blindness prevention programs will hopefully provide new evidences on cost effective ways to screen and manage glaucoma in the future. This article aims to highlight the burden of glaucoma and ways to address the challenges in developing countries.

Treatment outcomes of retinal vein occlusion in clinical practice in Nepal.

BACKGROUND: This study evaluated the treatment outcomes of retinal vein occlusion (RVO) in a routine clinical practice in Nepal. METHODS: This was a retrospective analysis of observational data of patients with RVO who attended the retina clinic of the Tilganga Institute of Ophthalmology from 1 November 2017 to 31 October 2018. The main outcome was the mean change in visual acuity (VA) at 12 months from the start of treatment. Other outcomes of interest were the mean change in central subfield thickness (CST) and the number of treatments over 12 months. RESULTS: A total of 99 eyes (of 99 patients) with RVO (60 - branch RVO [BRVO] and 39 - central RVO [CRVO] were available for the analysis. Eyes with CRVO had worse VA and CST at baseline. Eyes in both groups were similar for age, associated factors for RVO, duration of vision loss and the presence of ischemia at baseline. The mean (95% Confidence Interval [CI]) VA change at 12 months for BRVO was - 0.35 (- 0.46, - 0.23) logMAR (p < 0.001) from a mean (SD) of 0.75 (0.42) logMAR at baseline with 63% achieving VA < 0.3 logMAR while for CRVO it was - 0.35 (- 0.46, - 0.23) logMAR (p = 0.19) from 1.13 (0.61) logMAR at baseline and VA < 0.3 logMAR in 36%. The mean (95% CI) change in CST over 12 months was - 114 (- 189, - 40) µm (p = 0.003) from a mean (SD) of 423 (151) µm at baseline for BRVO and - 184(- 276, - 91) µm (p < 0.001) from 519 (213) µm for CRVO. Patients in both groups received a median of 2 bevacizumab injections over 12 months. Around 37% eyes were lost before 12 months' observation. The mean VA and CST trajectory in these eyes at their last visit was similar to those that completed 12 months. CONCLUSION: The outcomes of RVO over the 12 months were inferior and the number of treatments fewer than those of the clinical trials and other reports from routine clinical practice. Future studies to identify the treatment barriers are warranted to improve the treatment outcomes in our patients.

Vaccination against cocaine using a modifiable dendrimer nanoparticle platform.

Pharmacological therapies for the treatment of cocaine addiction have had disappointing efficacy, and the lack of recent developments in the clinical care of cocaine-addicted patients indicates a need for novel treatment strategies. Recent studies have shown that vaccination against cocaine to elicit production of antibodies that reduce concentrations of free drug in the blood is a promising method to protect against the effects of cocaine and reduce rates of relapse. However, the poorly immunogenic nature of cocaine remains a major hurdle to active immunization. Therefore, we hypothesized that strategies to increase targeted exposure of cocaine to the immune system may produce a more effective vaccine. To specifically direct an immune response against cocaine, in the present study we have conjugated a cocaine analog to a dendrimer-based nanoparticle carrier with MHC II-binding moieties that previously has been shown to activate antigen-presenting cells necessary for antibody production. This strategy produced a rapid, prolonged, and high affinity anti-cocaine antibody response without the need for an adjuvant. Surprisingly, additional evaluation using multiple adjuvant formulations in two strains of inbred mice found adjuvants were either functionally redundant or deleterious in the vaccination against cocaine using this platform. The use of conditioned place preference in rats after administration of this vaccine provided proof of concept for the ability of this vaccine to diminish cocaine reward. Together these data demonstrate the intrinsic efficacy of an immune-targeting dendrimer-based cocaine vaccine, with a vast potential for design of future vaccines against other poorly immunogenic antigens by substitution of the conjugated cargo.

Referral parameters for diagnosis of glaucoma in general eye clinic at Tilganga Institute of Ophthalmology.

OBJECTIVE: To find out the most common referral parameter among the glaucoma suspects patients from general eye clinic and to establish glaucoma diagnosis. METHODS: This study is a retrospective cohort hospital based study. Two hundred patients from January to February 2017 sent to glaucoma clinic as glaucoma suspects were re-evaluated meticulously by glaucoma specialist and were diagnosed as glaucoma, non glaucoma, suspects and ocular hypertension. RESULTS: Out of the 200 patients referred to glaucoma clinic as glaucoma suspects only19% were diagnosed to have glaucoma. The mean age at which glaucoma diagnosed was 55.29(14.4) compared to 41.6(15.1) in normal group. One hundred and sixty five patients were referred on the basis of suspicious optic nerve head, among them 14.5% (24/165) had glaucoma. This study showed that, open angle glaucoma (OAG) 28.9% was the most common type of total glaucoma diagnosed. The mean vertical cup discratio in the OAG group was 0.69±0.1 (0.4 -0.9) compared to 0.56 ± 0.11((0.2-0.8)(p=0.00) normal. The mean intra ocular pressure (IOP) in OAG group was 19.73 ±4.95(11-32) mmHg compared to 16.74± 3.36(10-30) mmHg (p=0.00) in normal group. The mean central corneal thickness (CCT) in OAG group was 533.05 ± 31.24µm (467-606) compared to normal was 534.9±33.6 µm (432-696) (p=0.670). CONCLUSIONS: Suspicious optic nerve head is the most common referral parameter between the general ophthalmologist and residents, but this study shows only few of them were diagnosed with glaucoma. This gives us a clue that the ophthalmologists and residents are to be trained better to help them identify the signs of glaucoma on the optic nerve head beside its size, which will reduce unnecessary burden to the resources of patients and hospital.

An enhanced bioluminescence-based Annexin V probe for apoptosis detection in vitro and in vivo.

The process of controlled cellular death known as apoptosis has an important central role not only in normal homeostatic maintenance of tissues, but also in numerous diseases such as cancer, neurodegenerative, autoimmune, and cardiovascular diseases. As a result, new technologies with the capability to selectively detect apoptotic cells represent a central focus of research for the study of these conditions. We have developed a new biosensor for the detection of apoptotic cells, incorporating the targeted selectivity for apoptotic cells from Annexin V with the sensitivity of bioluminescence signal generation from a serum-stable mutant of Renilla luciferase (RLuc8). Our data presents a complete characterization of the structural and biochemical properties of this new Annexin-Renilla fusion protein (ArFP) construct, as well as a validation of its ability to detect apoptosis in vitro. Moreover, this work represents the first report of a bioluminescent Annexin V apoptosis sensor utilized in vivo. With this new construct, we examine apoptosis within disease-relevant animal models of surgery-induced ischemia/reperfusion, corneal injury, and retinal cell death as a model of age-related macular degeneration. In each of these experiments, we demonstrate successful application of the ArFP construct for detection and bioluminescence imaging of apoptosis within each disease or treatment model. ArFP represents an important new tool in the continuously growing kit of technologies for apoptosis detection, and our results from both in vitro and in vivo experiments suggest a diverse range of potential clinically relevant applications including cancer therapeutic screening and efficacy analysis, atherosclerosis and cardiovascular disease detection, and the monitoring of any number of other conditions in which apoptosis has a central role.

Glutathione S-transferase pi isoform (GSTP1) expression in murine retina increases with developmental maturity.

BACKGROUND AND AIMS: Glutathione S-transferase pi isoform (GSTP1) is an intracellular detoxification enzyme that catalyzes reduction of chemically reactive electrophiles and is a zeaxanthin-binding protein in the human macula. We have previously demonstrated that GSTP1 levels are decreased in human age-related macular degeneration (AMD) retina compared to normal controls (Joshi et al., Invest Ophthalmol Vis Sci, e-abstract, 2009). We also showed that GSTP1 levels parallel survival of human retinal pigment epithelial (RPE) cells exposed to ultraviolet (UV) light, and GSTP1 over-expression protects them against UV light damage (Joshi et al., Invest Ophthalmol Vis Sci, e-abstract, 2010). In the present work, we determined the developmental time course of GSTP1 expression in murine retina and in response to light challenge. METHODS: Eyes from BALB/c mice at postnatal day 20, 1 month, and 2 months of age were prepared for retinal protein extraction and cryo sectioning, and GSTP1 levels in the retina were analyzed by Western blot and immunohistochemistry (IHC). Another group of BALB/c mice with the same age ranges was exposed to 1000 lx of white fluorescent light for 24 h, and their retinas were analyzed for GSTP1 expression by Western blot and IHC in a similar manner. RESULTS: GSTP1 levels in the murine retina increased in ascending order from postnatal day 20, 1 month, and 2 months of age. Moreover, GSTP1 expression in murine retina at postnatal day 20, 1 month, and 2 months of age increased in response to brief light exposure compared to age-matched controls under normal condition. CONCLUSIONS: GSTP1 expression in retina increases with developmental age in mice and accompanies murine retinal maturation. Brief exposure to light induces GSTP1 expression in the murine retina across various developmental ages. GSTP1 induction may be a protective response to light-induced oxidative damage in the murine retina.

Activating the Nrf2-mediated antioxidant response element restores barrier function in the alveolar epithelium of HIV-1 transgenic rats.

The master transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) regulates the expression of antioxidant and phase II-metabolizing enzymes by activating the antioxidant response element (ARE) and thereby protects cells and tissues from oxidative stress. Pulmonary complications remain the leading cause of death in human immunodeficiency virus (HIV)-1-infected individuals, who display systemic oxidative stress and glutathione deficiency that can be modeled in transgenic rats where HIV-1-related viral proteins decrease glutathione levels and cause epithelial barrier dysfunction within the alveolar space by as yet unknown mechanisms. We hypothesized that HIV-1-related proteins inhibit Nrf2-mediated antioxidant defenses and thereby disrupt the normally tight alveolar epithelial barrier. Nrf2 RNA silencing dampened Nrf2/ARE activity, decreased the expression of the tight junction proteins zonula occludens-1, occludin, and claudin-18, increased paracellular permeability of alveolar epithelial monolayers derived from wild-type rats, and therefore reproduced the effects of HIV-1 transgene expression on the epithelial barrier that we had previously described. In contrast, upregulating Nrf2 activity, either by plasmid-mediated overexpression or treatment with the Nrf2 activator sulforaphane, increased the expression of ARE-dependent antioxidants, including NAD(P)H dehydrogenase, quinone 1 and glutathione, improved the expression of tight junction proteins, and restored the ability to form tight barriers in alveolar epithelial cells from HIV-1 transgenic rats. Taken together, these new findings argue that HIV-1-related proteins downregulate Nrf2 expression and/or activity within the alveolar epithelium, which in turn impairs antioxidant defenses and barrier function, thereby rendering the lung susceptible to oxidative stress and injury. Furthermore, this study suggests that activating the Nrf2/ARE pathway with the dietary supplement sulforaphane could augment antioxidant defenses and lung health in HIV-1-infected individuals.

Alcohol ingestion disrupts alveolar epithelial barrier function by activation of macrophage-derived transforming growth factor beta1.

BACKGROUND: Chronic alcohol abuse causes oxidative stress and impairs alveolar epithelial barrier integrity, thereby rendering the lung susceptible to acute edematous injury. Experimentally, alcohol-induced oxidative stress increases the expression of transforming growth factor ß1 (TGFß1) in the lung; however, we do not know the precise contribution of various alveolar cells in this process. In the present study, we focused on cell-cell interactions between alveolar macrophages and epithelial cells and the potential mechanisms by which TGFß1 may become activated in the alveolar space of the alcoholic lung. METHODS: Primary alveolar macrophages and epithelial cells were isolated from control- and alcohol-fed Sprague-Dawley rats. Expression of TGFß1 and the epithelial integrin αvß6 were examined by real time PCR and either immunocytochemistry or flow cytometry. Alveolar epithelial cells were cultured on transwell supports in the presence of macrophage cell lysate from control- or alcohol-fed rats or in the presence of viable macrophages ± alcohol. Epithelial barrier function was assessed by transepithelial resistance (TER) and paracellular flux of Texas Red dextran. RESULTS: TGFß1 expression was increased in alveolar macrophages from alcohol-fed rats, and TGFß1 protein was predominantly membrane-bound. Importantly, alveolar macrophage cellular lysate from alcohol-fed rats decreased TER and increased paracellular dextran flux in primary alveolar epithelial cell monolayers as compared to the lysates from control-fed rats. Alcohol-induced epithelial barrier dysfunction was prevented by anti-TGFß1 antibody treatment, indicating the presence of bioactive TGFß1 in the macrophage lysate. In addition, co-culturing macrophages and epithelial cells in the presence of alcohol decreased epithelial barrier function, which also was prevented by anti-TGFß1 and anti-αvß6 treatment. In parallel, chronic alcohol ingestion in vivo, or direct treatment with active TGFß1 in vitro, increased the expression of αvß6 integrin, which is known to activate TGFß1, in alveolar epithelial cells. CONCLUSIONS: Taken together, these data suggest that interactions between alveolar epithelial cells and macrophages contribute to the alcohol-mediated disruption of epithelial barrier function via the expression and activation of TGFß1 at points of cell-cell contact.

Chronic alcohol ingestion in rats decreases Krüppel-like factor 4 expression and intracellular zinc in the lung.

BACKGROUND: Chronic alcohol ingestion alters the dynamic balance between granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor beta1 (TGFß1) signaling within the alveolar space and, in parallel, impairs alveolar macrophage and epithelial cell function by inhibiting expression of the zinc importer ZIP4 and decreasing zinc bioavailability in the alveolar compartment. As the transcription factor Krüppel-like factor 4 (KLF4 ) binds to ZIP4 , we hypothesized that alcohol exposure and consequent perturbations in GM-CSF and TGFß1 signaling could decrease cellular KLF4 expression and/or binding as a mechanism by which it inhibits ZIP4 expression and decreases cellular zinc levels. METHODS AND RESULTS: Alcohol exposure in vitro or chronic ingestion in vivo decreased KLF4 expression in alveolar macrophages and epithelial cells. Treatment with GM-CSF or TGFß1 showed an enhancing or dampening effect on KLF4 expression and binding, respectively. Further, treatment of a rat alveolar macrophage cell line with alcohol in vitro for 4 weeks decreased the expression of the zinc transporters ZIP4 and ZNT1, and of the zinc storage protein metallothionein 1. In parallel, treating these macrophages with KLF4 siRNA decreased ZIP4 expression and decreased cellular zinc and phagocytic capacity to levels equivalent to those following alcohol exposure. In epithelial monolayers, transepithelial electrical resistance (TER) was significantly decreased by alcohol ingestion as compared with control diets, and it was restored by in vitro GM-CSF treatment. In contrast, in vitro TGFß1 treatment of the epithelial monolayers from control-fed rats significantly decreased TER as compared with untreated control monolayers. CONCLUSIONS: Taken together, these results suggest that within the alveolar space, chronic alcohol exposure decreases KLF4 and ZIP4 expression and consequently decreases zinc transport into cells, which, in turn, impairs their function. Furthermore, the dynamic decrease in the relative influence of GM-CSF versus TGFß1 could mediate the zinc deficiency and consequent cellular dysfunction that characterize the "alcoholic lung" phenotype.

HIV-1 transgene expression in rats induces differential expression of tumor necrosis factor alpha and zinc transporters in the liver and the lung.

BACKGROUND: Highly effective antiviral treatment can suppress HIV-1 infection, but the chronic effects of HIV-1-related viral proteins, including gp120 and Tat, on organs such as the lungs can be damaging. HIV-1 transgenic rodent models are useful for studying the systemic effects of these proteins independently of viral infection. We have previously shown that HIV-1 transgene expression (and therefore, HIV-1-related protein expression) in rats decreases alveolar macrophage zinc levels and phagocytic capacity by unknown mechanisms. We hypothesized that HIV-1 transgene expression induces chronic inflammation and zinc sequestration within the liver and thereby decreases zinc bioavailability in the lung. We examined the expression of the pro-inflammatory cytokine, tumor necrosis factor alpha (TNFα), the zinc storage protein, metallothionein (MT1), and the zinc exporter, ZNT1 in the livers and the lungs of wild type and HIV-1 transgenic rats ± dietary zinc supplementation. In addition, we measured zinc levels, the zinc importing protein ZIP1, and the phagocytic capacity in the alveolar macrophages. RESULTS: HIV-1 transgene expression increased the liver-specific expression of TNFα, suggesting a chronic inflammatory response within the liver in response to HIV-1-related protein expression. In parallel, HIV-1 transgene expression significantly increased MT1 and ZNT1 expression in the liver as compared to the lung, a pattern that is consistent with zinc sequestration in the liver as occurs during systemic inflammation. Further, HIV-1 transgene expression decreased intracellular zinc levels and increased expression of ZIP1 in the alveolar macrophages, a pattern consistent with zinc deficiency, and decreased their bacterial phagocytic capacity. Interestingly, dietary zinc supplementation in HIV-1 transgenic rats decreased gene expression of TNFα, MT1, and ZNT1 in the liver while simultaneously increasing their expression in the lung. In parallel, zinc supplementation increased alveolar macrophage intracellular zinc levels and bacterial phagocytic capacity in HIV-1 transgenic rats. CONCLUSION: Taken together, these findings suggest that chronic HIV-1-related protein expression causes liver inflammation and zinc sequestration, which in turn limits zinc bioavailability in the lung and thereby impairs alveolar macrophage phagocytic function. Importantly, dietary zinc supplementation decreases liver inflammation and zinc sequestration and restores alveolar macrophage phagocytic function in HIV-1 transgenic rats, a result with potential clinical implications for improving lung health in HIV-1-infected individuals.

Chronic alcohol ingestion exacerbates lung epithelial barrier dysfunction in HIV-1 transgenic rats.

BACKGROUND: Alcohol abuse and HIV-1 infection frequently coexist, and these individuals are at high risk for serious lung infections and respiratory failure. Although alcohol ingestion and HIV-1 transgene expression have been shown to independently cause oxidative stress and disrupt alveolar epithelial barrier function in experimental models, their interactive effects have not been examined. METHODS AND RESULTS: In this study, we determined that chronic alcohol ingestion (12 weeks) exacerbated the already significant defects in alveolar epithelial paracellular permeability and lung liquid clearance in HIV-1 transgenic rats. Further, immunocytochemical analyses of tight junction protein expression in primary alveolar epithelial cells showed that occludin and zonula occludens-1 localization within the plasma membrane was more disrupted than in either condition alone, consistent with the observed defects in epithelial barrier function. Interestingly, expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), the transcription factor required to activate the antioxidant-response element, was decreased in primary alveolar epithelial cells isolated from HIV-1 transgenic rats. In parallel, exposing lung epithelial cells in vitro to either alcohol or the HIV-related protein gp120 also decreased Nrf2 expression. Importantly, treatment with procysteine, which increases thiol antioxidants including glutathione, improved tight junction protein localization in the plasma membrane and restored alveolar epithelial barrier function in alcohol-fed HIV-1 transgenic rats. CONCLUSIONS: These results provide novel evidence that HIV-related proteins and alcohol together causes more barrier dysfunction in the lung epithelium than either stress alone. However, these significant effects on the alveolar barrier can be mitigated by augmenting the thiol antioxidant pool, a strategy with potential clinical applications in subjects who are highly vulnerable to lung disease because of coexistent alcohol abuse and HIV infection.

Zinc supplementation restores PU.1 and Nrf2 nuclear binding in alveolar macrophages and improves redox balance and bacterial clearance in the lungs of alcohol-fed rats.

BACKGROUND: Chronic alcohol abuse causes oxidative stress, impairs alveolar macrophage immune function, and increases the risk of pneumonia and acute lung injury. Recently we determined that chronic alcohol ingestion in rats decreases zinc levels and macrophage function in the alveolar space; provocative findings in that zinc is essential for normal immune and antioxidant defenses. Alveolar macrophage immune function depends on stimulation by granulocyte/monocyte colony-stimulating factor, which signals via the transcription factor PU.1. In parallel, the antioxidant response element signals via the transcription factor Nrf2. However, the role of zinc bioavailability on these signaling pathways within the alveolar space is unknown. METHODS: To determine the efficacy of dietary zinc supplementation on lung bacterial clearance and oxidative stress, we tested 3 different groups of rats: control-fed, alcohol-fed, and alcohol-fed with zinc supplementation. Rats were then inoculated with intratracheal Klebsiella pneumoniae, and lung bacterial clearance was determined 24 hours later. Isolated alveolar macrophages were isolated from uninfected animals and evaluated for oxidative stress and signaling through PU.1 and Nrf2. RESULTS: Alcohol-fed rats had a 5-fold decrease in lung bacterial clearance compared to control-fed rats. Dietary zinc supplementation of alcohol-fed rats normalized bacterial clearance and mitigated oxidative stress in the alveolar space, as reflected by the relative balance of the thiol redox pair cysteine and cystine, and increased nuclear binding of both PU.1 and Nrf2 in alveolar macrophages from alcohol-fed rats. CONCLUSIONS: Dietary zinc supplementation prevents alcohol-induced alveolar macrophage immune dysfunction and oxidative stress in a relevant experimental model, suggesting that such a strategy could decrease the risk of pneumonia and lung injury in individuals with alcohol use disorders.

HIV-1 transgene expression in rats causes oxidant stress and alveolar epithelial barrier dysfunction.

BACKGROUND: HIV-infected individuals are at increased risk for acute and chronic airway disease even though there is no evidence that the virus can infect the lung epithelium. Although HIV-related proteins including gp120 and Tat can directly cause oxidant stress and cellular dysfunction, their effects in the lung are unknown. The goal of this study was to determine the effects of HIV-1 transgene expression in rats on alveolar epithelial barrier function. Alveolar epithelial barrier function was assessed by determining lung liquid clearance in vivo and alveolar epithelial monolayer permeability in vitro. Oxidant stress in the alveolar space was determined by measuring the glutathione redox couple by high performance liquid chromatography, and the expression and membrane localization of key tight junction proteins were assessed. Finally, the direct effects of the HIV-related proteins gp120 and Tat on alveolar epithelial barrier formation and tight junction protein expression were determined. RESULTS: HIV-1 transgene expression caused oxidant stress within the alveolar space and impaired epithelial barrier function even though there was no evidence of overt inflammation within the airways. The expression and membrane localization of the tight junction proteins zonula occludens-1 and occludin were decreased in alveolar epithelial cells from HIV-1 transgenic rats. Further, treating alveolar epithelial monolayers from wild type rats in vitro with recombinant gp120 or Tat for 24 hours reproduced many of the effects on zonula occludens-1 and occludin expression and membrane localization. CONCLUSION: Taken together, these data indicate that HIV-related proteins cause oxidant stress and alter the expression of critical tight junction proteins in the alveolar epithelium, resulting in barrier dysfunction.

Zinc deficiency mediates alcohol-induced alveolar epithelial and macrophage dysfunction in rats.

Chronic alcohol abuse impairs both alveolar epithelial and macrophage function, and renders individuals susceptible to acute lung injury, pneumonia, and other serious lung diseases. Zinc deficiency, which is known to impact both epithelial and immune cell functions, is also associated with alcohol abuse. In this study, chronic alcohol ingestion (6 wk) in rats altered expression of key zinc transporters and storage proteins in the small intestine and the lung, and decreased zinc levels in the alveolar compartment. Zinc supplementation of alveolar epithelial monolayers derived from alcohol-fed rats in vitro, or of the diets of alcohol-fed rats in vivo, restored alveolar epithelial barrier function, and these improvements were associated with salutary changes in tight junction protein expression and membrane localization. In parallel, dietary zinc supplementation increased intracellular zinc levels, GM-CSF receptor expression, and bacterial phagocytic capacity in the alveolar macrophages of alcohol-fed rats. Together, these studies implicate zinc deficiency as a novel mechanism mediating alcohol-induced alveolar epithelial and macrophage dysfunction. Importantly, these findings argue that dietary supplementation can overcome alcohol-induced zinc deficiency and restore alveolar epithelial and macrophage function, and therefore could be an effective treatment for the susceptible alcoholic lung phenotype.

Na,K-ATPase expression is increased in the lungs of alcohol-fed rats.

BACKGROUND: Alcohol abuse independently increases the risk of developing the acute respiratory distress syndrome (ARDS), a disease characterized by diffuse alveolar epithelial damage, lung edema, and consequent severe hypoxemia. Chronic alcohol abuse increases alveolar epithelial permeability both in vitro and in vivo, in part due to altered tight junction formation. However, both alcohol-fed animals and otherwise healthy alcoholic humans do not have pulmonary edema at baseline, even though their lungs are highly susceptible to acute edematous injury in response to inflammatory stresses. This suggests that active fluid transport by the alveolar epithelium is preserved or even augmented in the alcoholic lung. Chronic alcohol ingestion increases expression of apical sodium channels in the alveolar epithelium; however, its effects on the Na,K-ATPase complex that drives sodium and fluid transport out of the alveolar space have not been examined. METHODS: Age- and gender-matched Sprague-Dawley rats were fed the Lieber-DeCarli liquid diet containing either alcohol or an isocaloric substitution (control diet) for 6 weeks. Gene and protein expression of lung Na,K-ATPase alpha1, alpha2, and beta1 subunits were quantified via real-time PCR and immunobiological analyses, respectively. Alcohol-induced, Na,K-ATPase-dependent epithelial barrier dysfunction was determined by calculating lung tissue wet:dry ratios following an ex vivo buffer-perfused challenge for 2 hours in the presence of ouabain (10(-4) M), a Na,K-ATPase inhibitor. RESULTS: Chronic alcohol ingestion significantly increased gene and protein expression of each Na,K-ATPase subunit in rat lungs. Immunohistochemical analyses of the alcoholic lung also revealed that protein expression of the Na,K-ATPase alpha1 subunit was increased throughout the alveolar epithelium. Additionally, lungs isolated from alcohol-fed rats developed more edema than comparably treated lungs from control-fed rats, as reflected by increased lung tissue wet:dry ratios. CONCLUSIONS: These findings indicate that chronic alcohol ingestion, which is known to increase alveolar epithelial paracellular permeability, actually increases the expression of Na,K-ATPase in the lung as a compensatory mechanism. This provides a potential explanation as to why the otherwise healthy alcoholic does not have evidence of pulmonary edema at baseline.

HIV-1-transgene expression in rats decreases alveolar macrophage zinc levels and phagocytosis.

HIV-1 infection impairs alveolar macrophage immune function and renders patients susceptible to pneumonia by poorly understood mechanisms. Alveolar macrophage maturation and function depends on granulocyte-macrophage colony-stimulating factor (GM-CSF), which is produced and secreted by the alveolar epithelium. Macrophages respond to GM-CSF through the GM-CSF receptor (GM-CSFR), which has a binding subunit (GM-CSFRalpha) and a signaling subunit (GM-CSFRbeta). In this study, we measured GM-CSFR expression and alveolar macrophage function in a transgene HIV-1 rat model (NL4-3Delta gag/pol); this construct bears a pro-virus with gag and pol deleted, but other HIV-1-related proteins, such as gp120 and Tat, are expressed, and the rats develop an AIDS-like phenotype as they age. We first determined that HIV-1-transgenic expression selectively decreased alveolar macrophage expression of GM-CSFRbeta and impaired bacterial phagocytosis in vitro. Next, we examined the role of zinc (Zn) deficiency as a potential mechanism underlying these effects, and determined that HIV-1-transgenic rats have significantly lower levels of Zn in the alveolar space and macrophages. To test the direct effect of Zn deficiency on macrophage dysfunction, we treated rat alveolar macrophage cell line with a Zn chelator, N,N,N',N'-tetrakis-(2-pyridyl-methyl) ethylenediamine, and this decreased GM-CSFRbeta expression and phagocytosis. In parallel, treatment with Zn acetate in vitro for 48 hours restored intracellular Zn levels and phagocytic function in alveolar macrophages from HIV-1-transgenic rats. Taken together, these data suggest that pulmonary Zn deficiency could be one of the mechanisms by which chronic HIV-1 infection impairs alveolar macrophage immune function and renders these individuals susceptible to serious lung infections.

The alcoholic lung: epidemiology, pathophysiology, and potential therapies.

Epidemiological evidence gathered only in the past decade reveals that alcohol abuse independently increases the risk of developing the acute respiratory distress syndrome by as much as three- to fourfold. Experimental models and clinical studies are beginning to elucidate the mechanisms underlying this previously unrecognized association and are revealing for the first time that chronic alcohol abuse causes discrete changes, particularly within the alveolar epithelium, that render the lung susceptible to acute edematous injury in response to sepsis, trauma, and other inflammatory insults. Recent studies in relevant animal models as well as in human subjects are identifying common mechanisms by which alcohol abuse targets both the alveolar epithelium and the alveolar macrophage, such that the risks for acute lung injury and pulmonary infections are inextricably linked. Specifically, chronic alcohol ingestion decreases the levels of the antioxidant glutathione within the alveolar space by as much as 80-90%, and, as a consequence, impairs alveolar epithelial surfactant production and barrier integrity, decreases alveolar macrophage function, and renders the lung susceptible to oxidant-mediated injury. These changes are often subclinical and may not manifest as detectable lung impairment until challenged by an acute insult such as sepsis or trauma. However, even otherwise healthy alcoholics have evidence of severe oxidant stress in the alveolar space that correlates with alveolar epithelial and macrophage dysfunction. This review focuses on the epidemiology and the pathophysiology of alcohol-induced lung dysfunction and discusses potential new treatments suggested by recent experimental findings.

Extraction and carrier-facilitated transport of amino acids using synthetic non-cyclic receptors through bulk liquid membrane.

The extraction and carrier-facilitated transport of amino acids (leucine, valine and glycine) was studied through chloroform bulk liquid membrane system using a series of non-cyclic receptors such as diethylene glycol (1), diethylene glycol dimethyl ether (2), diethylene glycol dibutyl ether (3), diethylene glycol dibenzoate (4), triethylene glycol (5) and tetraethylene glycol (6). The amount of amino acid extracted and transported depends mainly upon the structure and the concentration of the receptors and also on the concentration of amino acid. The receptors 1 to 4, having small chain length and flexible end groups, formed stable complexes with amino acids, and the flexibility of receptors in different conformational forms was responsible for their carrier ability, while the receptors 5 and 6, having larger chain length showed poor carrier ability. Hydrophobicity of amino acids also play an important role in the extraction as well as transport process.